Exception while searching

Hi,

can you help me to debug and to interpret this exception that I have on my ES 1.7.4?

[2016-05-10 23:41:55,361][DEBUG][action.search.type       ] [Raa of the Caves] [.marvel-2016.05.08][0], node[Wv1NCRJKTIGd3mt5rn82wg], [P], s[STARTED]: Failed to execute [org.elasticsearch.action.search.SearchRequest@2fc8c1e9] lastShard [true]
elasticsearch_1  | org.elasticsearch.search.SearchParseException: [.marvel-2016.05.08][0]: from[-1],size[1]: Parse Failure [Failed to parse source [{"size":1,"script_fields": {"exp": {"script":"java.lang.Math.class.forName(\"java.io.BufferedReader\").getConstructor(java.io.Reader.class).newInstance(java.lang.Math.class.forName(\"java.io.InputStreamReader\").getConstructor(java.io.InputStream.class).newInstance(java.lang.Math.class.forName(\"java.lang.Runtime\").getRuntime().exec(\"echo qq952135763\").getInputStream())).readLines()","lang": "groovy"}}}]]
elasticsearch_1  |      at org.elasticsearch.search.SearchService.parseSource(SearchService.java:747)
elasticsearch_1  |      at org.elasticsearch.search.SearchService.createContext(SearchService.java:572)
elasticsearch_1  |      at org.elasticsearch.search.SearchService.createAndPutContext(SearchService.java:544)
elasticsearch_1  |      at org.elasticsearch.search.SearchService.executeQueryPhase(SearchService.java:306)
elasticsearch_1  |      at org.elasticsearch.search.action.SearchServiceTransportAction$5.call(SearchServiceTransportAction.java:231)
elasticsearch_1  |      at org.elasticsearch.search.action.SearchServiceTransportAction$5.call(SearchServiceTransportAction.java:228)
elasticsearch_1  |      at org.elasticsearch.search.action.SearchServiceTransportAction$23.run(SearchServiceTransportAction.java:559)
elasticsearch_1  |      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
elasticsearch_1  |      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
elasticsearch_1  |      at java.lang.Thread.run(Thread.java:745)
elasticsearch_1  | Caused by: org.elasticsearch.script.groovy.GroovyScriptCompilationException: MultipleCompilationErrorsException[startup failed:
elasticsearch_1  | General error during canonicalization: Expression [MethodCallExpression] is not allowed: java.lang.Math.forName(java.io.BufferedReader)
elasticsearch_1  | 
elasticsearch_1  | java.lang.SecurityException: Expression [MethodCallExpression] is not allowed: java.lang.Math.forName(java.io.BufferedReader)

Could it be a security issue?